An augmented reality (AR) technique is known, which is to superimpose and display an object such as image data or text data that does not exist in the real world on a real-world image acquired by imaging a real-world environment and displayed on a display and to provide a synthesized image as if the object existed in the real world. The object may be image data including text data or may be image data that evokes a characteristic meaning by a shape, a color, and the like of the object. Hereinafter, the object is referred to as an AR content.
Since a user who views the synthesized image may recognize that information displayed as the AR content is associated with a real space, the user may acquire a larger amount of information, compared with a case where the user visually recognizes a simple real-world environment.
The AR technique includes a technique that is referred to as location-based AR and a technique that is referred to as vision-based AR. The location-based AR is to acquire positional information of a terminal provided with a camera and information on an orientation from a GPS sensor or the like and determine, based on the positional information and the information on the orientation, details of an AR content to be superimposed and displayed on an image acquired by the camera and a position at which the AR content is superimposed and displayed.
Vision-based AR is to execute image recognition such as object recognition or space recognition on image data acquired by the camera. Then, if vision-based AR confirms that the image data is data of an image acquired by imaging a specific object, vision-based AR superimposes and displays an AR content associated with and prepared for the specific object based on a result of the image recognition (refer to, for example, Japanese Laid-open Patent Publications Nos. 2002-092647 and 2004-048674). In general, if a marker is recognized as the specific object, vision-based AR is referred to as marker vision-based AR in some cases. If an object other than markers is recognized as the specific object, vision-based AR is referred to as marker-less vision-based AR in some cases.
For the AR technique, a task of preparing an AR content is performed. For example, in vision-based AR, image data and text data that are to be displayed as the AR content are generated, and a position at which the AR content is arranged is set using the specific object as a reference. The task of preparing the AR content and a computer process are referred to as authoring. In this manner, the AR content is prepared by the authoring and superimposed and displayed by imaging a real-world space including the specific object by the camera after the preparation.
For example, an information processing device that is configured to support an authoring task to be performed by a user is known (refer to, for example, Japanese Laid-open Patent Publication No. 2012-168798). The information processing device displays an input image on a screen and detects a position specified by the user. Then, the information processing device calculates a three-dimensional position corresponding to the specified position and located in an augmented reality space, associates the three-dimensional position with a virtual object, stores the three-dimensional position and the virtual object.
Specifically, an image recognition unit that is included in the information processing device recognizes the specific object from the input image. Then, a calculator that is included in the information processing device calculates a position that corresponds to the position specified by the user and is located on a plane within a virtual space including a surface of the recognized object. The calculated position is a position at which the virtual object is arranged. In addition, the position at which the virtual object is arranged is adjusted in a depth direction in a virtual real space by providing an offset value to the information processing device from the user.